U.S. patent number 6,172,147 [Application Number 09/233,806] was granted by the patent office on 2001-01-09 for additive for production of highly workable mortar cement.
This patent grant is currently assigned to W. R. Grace & Co.-Conn.. Invention is credited to Angel Abelleira, John Hallock.
United States Patent |
6,172,147 |
Abelleira , et al. |
January 9, 2001 |
Additive for production of highly workable mortar cement
Abstract
Mortar cement additives provide workability while retaining
strength by employing a multi-stage polymer comprising a
hydrophobically-modified, ionically-soluble polymer stage, the
polymer being soluble at a pH of 6 and above; and an air-entraining
agent. The additives also employ, as optional ingredients, set
retarding agents and superplasticizers. Examplary methods of the
invention involve addition of the multi-stage polymer and an air
entraining agent to the mortar cement, preferably during
intergrinding of Portland cement in the mill. Cement compositions
comprising the polymer and an air-entraining agent are also
disclosed.
Inventors: |
Abelleira; Angel (Nashua,
NH), Hallock; John (Columbia, MD) |
Assignee: |
W. R. Grace & Co.-Conn.
(New York, NY)
|
Family
ID: |
25235343 |
Appl.
No.: |
09/233,806 |
Filed: |
May 5, 1998 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
822165 |
Mar 21, 1997 |
5782972 |
|
|
|
Current U.S.
Class: |
524/95; 524/156;
524/157; 524/158; 524/230; 524/293; 524/3; 524/313; 524/320;
524/366; 524/369; 524/372; 524/376; 524/4 |
Current CPC
Class: |
C04B
24/16 (20130101); C04B 24/2641 (20130101); C04B
24/2688 (20130101); C04B 24/32 (20130101); C04B
28/02 (20130101); C04B 28/02 (20130101); C04B
24/2641 (20130101); C04B 24/2641 (20130101); C04B
28/02 (20130101); C04B 24/2688 (20130101); C04B
28/02 (20130101); C04B 24/2647 (20130101); C04B
24/32 (20130101); C04B 2103/0053 (20130101); C04B
2103/52 (20130101); C04B 2103/0059 (20130101); C04B
2103/304 (20130101); C04B 2103/0053 (20130101); C04B
2103/22 (20130101); C04B 2103/304 (20130101); C04B
2103/32 (20130101); C04B 2103/22 (20130101); C04B
2103/304 (20130101) |
Current International
Class: |
C04B
24/32 (20060101); C04B 24/16 (20060101); C04B
28/00 (20060101); C04B 24/00 (20060101); C04B
28/02 (20060101); C04B 24/26 (20060101); C04B
024/00 (); C04B 024/26 (); C04B 038/00 () |
Field of
Search: |
;524/95,156,157,158,230,243,313,320,366,369,370,376 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
5266646 |
November 1993 |
Eisenhart et al. |
5451641 |
September 1995 |
Eisenhart et al. |
|
Primary Examiner: Szekely; Peter A.
Attorney, Agent or Firm: Leon; Craig K. Baker; William
L.
Parent Case Text
This is a divisional of application Ser. No. 08/822,165, filed Mar.
21, 1997, now U.S. Pat. No. 5,782,972
Claims
We claim:
1. A mortar cement additive comprising: 6-30% by total weight of
the mortar cement additive of a multi-stage polymer comprising a
hydrophobically-modified, ionically-soluble polymer stage, the
polymer being soluble at a pH of 6 and above; said multi-stage
polymer comprising at least two polymer stages wherein:
(A) at least one of said polymer stages is an ionically-soluble
polymer, the ionically-soluble polymer being polymerized from a
monomer mixture comprising:
(a) about 0.1 to about 55% by weight hydrophobic monomer having the
formula ##STR2##
R.sub.1 and R.sub.5 independently are (C.sub.1 -C.sub.30) alkyl, a
(mono, di-, or tri-) (C.sub.1 -C.sub.30) alkyl-substituted phenyl
ring, or a sorbitan fatty ester; R.sub.2, R.sub.3 and R.sub.4
independently are --H or (C.sub.1 -C.sub.10) aklyl, aryl or
alkylaryl; a is 0 or 1; b is 0 to 50; c is 0 to 150; d is 0 to 50;
e is equal to or greater than 1 and X is a group containing at
least one ethylenic double bond;
(b) about 10 to about 69% by weight (C.sub.3 -C.sub.30)
ethylenically-unsaturated, ionizable monomer, and
(c) about 0.1 to about 90% by weight nonionic (C.sub.2 -C.sub.30)
ethylenically-unsaturated monomer, and
(d) 0 to about 10% by weight multi-functional compounds;
(B) the ionically-soluble polymer is physically or chemically
attached to the polymer particle such that, upon neutralizing the
ionically-soluble polymer with base or acid, at least a portion of
said ionically-soluble polymer remains attached to the remainder of
the polymer particle; and
(C) the ionically-soluble polymer comprises from about 1% to about
99% by weight of the polymer particle; and
said mortar cement additive further comprising, in the amount of
0.5 to 5.0% by total weight additive, an air entraining agent
selected from the group consisting of fatty alkanolamides,
ethoxylated fatty amines, ethoxylated fatty acids, ethoxylated
triglycerides, ethoxylated alkylphenols, ethoxylated alcohols,
alkyl ethoxylates, alkylaryl ethoxylates, amine ethoxylates, amine
oxides, betaines, fatty alkyl ether sulfates, fatty alkylaryl ether
sulfates, alkyl benzene sulfonates, sulfosuccinates, and fatty
sulfonates.
2. The additive of claim 1 wherein said air entraining agent
comprises ethylene oxide groups.
3. The additive of claim 1 further comprising a set retarder.
4. The additive of claim 1 further comprising a superplasticizer
comprising an EO/PO comb polymer.
5. The additive of claim 1 wherein said multi-stage polymer
comprises an alkali-soluble acrylic polymer emulsion.
6. The additive of claim 2 wherein said additive further comprises
a superplasticizer comprising an EO/PO comb polymer.
7. The additive of claim 1 wherein said air entraining agent is
soluble at a pH of 3-6 and 10-11.
8. The additive of claim 3 wherein said set retarder is selected
from the group consisting of monosaccharides, disaccharides,
polysacchardies, polyhydroxy polycarboxylic compounds,
lignosulfonic acid and salts thereof; water-soluble salts of boric
acid, and zinc oxide.
9. The additive of claim 3 wherein said set retarder is
sucrose.
10. The additive of claim 6 wherein said EO/PO comb polymer is a
polyacrylic acid having pendant polyethylene oxide and
polypropylene oxide pendant groups.
11. The additive of claim 1 in the form of an emulsion.
12. The additive of claim 11 comprising water in the amount of
20-80% by weight.
13. The additive of claim 1 wherein said air entraining agent is a
fatty alkanolamide.
14. The additive of claim 1 wherein said air entraining agent is an
ethoxylated fatty amine.
15. The additive of claim 1 wherein said air entraining agent is an
ethoxylated fatty acid.
16. The additive of claim 1 wherein said air entraining agent is an
ethoxylated triglyceride.
17. The additive of claim 1 wherein said air entraining agent is an
ethoxylated alkylphenol.
18. The additive of claim 1 wherein said air entraining agent is an
ethoxylated alcohol.
19. The additive of claim 1 wherein said air entraining agent is an
alkyl ethoxylate.
20. The additive of claim 1 wherein said air entraining agent is an
alkylaryl ethoxylate.
21. The additive of claim 1 wherein said air entraining agent is an
amine ethoxylate.
22. The additive of claim 1 wherein said air entraining agent is an
amine oxide.
23. The additive of claim 1 wherein said air entraining agent is a
betaine.
24. The additive of claim 1 wherein said air entraining agent is a
fatty alkyl or alkylaryl ether sulfate.
25. The additive of claim 1 wherein said air entraining agent is an
alkyl benzene sulfonate.
26. The additive of claim 1 wherein said air entraining agent is a
sulfosuccinate.
27. The additive of claim 1 wherein said air entraining agent is a
fatty sulfonate.
Description
FIELD OF THE INVENTION
The present invention relates to additives for hydraulic cement
compositions. More particularly, this invention concerns additives
for hydraulic cement which are particularly useful in Portland
cement compositions such as masonry cements used for bonding
bricks, blocks, and other masonry units.
BACKGROUND OF THE INVENTION
Portland masonry cements are compositions produced particularly for
use by masons in the bonding of bricks, blocks, and other masonry
units. Such cements are typically mixed prior to use with a fine
aggregate, usually sand, and water. It is desirable that the wet
mortar have a high degree of plasticity for working (e.g.,
trowelling) by the mason, as well as other desirable properties
such as good "board life" (i.e., a long working time).
Masonry cements are produced by intergrinding Portland cement
(containing gypsum for proper setting time regulation), with,
generally, from about 20 to 65%, based on the total weight, of a
solid material such as limestone, chalk, talc, pozzolans, clay,
gypsum, or combinations of such. Limestone is most often the
ingredient interground with the Portland cement because of its good
plasticity enhancing properties. Such masonry cements are ground to
a greater degree of fineness than most Portland cements intended
for use in structural concretes. The finer grind of masonry cements
improves the plasticity of the finished mortar products.
As discussed in U.S. Pat. No. 5,294,256, additive products are sold
for mixture with the masonry cement to add certain desirable
properties to the masonry cement composition. It is common practice
to mix such additive products with the cement during the
intergrinding of the cement with the gypsum, limestone, etc.
In U.S. Pat. Nos. 3,865,601 and 3,885,985, additive products of the
above type are described. The additives described therein comprise
an aqueous oil-in-water emulsion containing water, a
water-insoluble, water-repelling acid component (e.g., tall oil),
an emulsifier (e.g., a salt of such an acid), and a setting time
retarding agent (e.g., sucrose). This additive product is
advantageously dispersible in water which reduces the risk of it
being overdosed. The additive may also contain an air-entraining
agent as an additional optional component.
An improved emulsion additive product is described in U.S. Pat. No.
4,375,987. In addition to the above constituents, this additive
comprised an emulsion stabilizer such as glycol which prevents an
oil-in-water emulsion from destabilizing when exposed to freezing
temperatures during shipping or storage prior to use.
As explained in U.S. Pat. No. 5,294,256, it has been necessary to
add further water retention agents, such as cellulose ether, during
the grinding process, to improve the plasticity of Portland masonry
cements. Conventional water retention agents cause the emulsion
additives described above to destabilize and hence must be added as
a separate feed stream, often as a dry powder. This method is
inconvenient, may increase manufacturing costs, and increases the
risk of overdosing the batch with the water retention agent. These
conventional water retention agents also may entrain large
quantities of air, which may be undesirable where high strength is
concerned. Thus, U.S. Pat. No. 5,294,256 taught the use of an
improved additive comprising an oil-in-water emulsion having a
solids portion comprised of a major proportion of a
water-insoluble, water-repelling acid component selected from the
group consisting of fatty acids, rosin acids, and mixtures thereof,
a set retarding component for the hydraulic cement, and a polymer
selected from polyvinyl acetate, polyvinyl alcohol, hydroxypropyl
substituted polysaccharides, or mixtures thereof.
Despite the availability of various mortar cement admixtures, the
present inventors believe that a novel additive is needed for
obtaining a mortar cement that has a satisfactory workability from
the subjective viewpoint of the mason who is applying the mortar
between the bricks or other masonry units, while providing for a
relatively low air content (when compared to masonry cements) to
maintain mortar strength. In particular, it is desired to discover
a mortar cement additive which can obtain a maximum air content of
14% or less, as required in Type S and Type M mortar cements, as
summarized in the table below:
Type N Type S Type M Masonry cement 21 19 19 Mortar cement 16 14
14
Cement manufacturers need to be especially careful when targeting
the 14% maximum air content mark, and typically seek a maximum air
content of about 12% as safety measure to avoid exceeding the 14%
threshold whereby a weakened masonry structure is obtained
Accordingly, the need for a novel mortar cement additive is
heightened somewhat in view of the need for obtaining a desired
strength as provided by a relatively low air content while
retaining workability in the mortar.
SUMMARY OF THE INVENTION
In surmounting disadvantages of prior art masonry mortar additives,
the present inventors have discovered a novel mortar additive
composition that provides the desired strength while providing a
workable rheology through controlling the maximum air content such
that it does not exceed 14% in the mortar cement. Surprisingly, the
present invention achieves this goal by combining a polymer that
has heretofore been seen as entraining a superfluity of air, and,
secondly, an air entraining agent.
An exemplary masonry additive of the present invention thus
comprises: (1) water (20-80% wt.); (2) a multi-stage polymer
comprising a hydrophobically-modified, ionically-soluble polymer
stage (6-30% based on total weight additive), the polymer being
soluble at a pH of 6 and above; and (3) an air-entraining agent
(0.1-5.0% based on total weight of additive). An exemplary method
of the present invention for modifying a mortar cement comprises
adding the foregoing components, preferably premixed together as
one liquid, into the mortar cement. More preferably, the components
are introduced into the intergrinding of the mortar cement
production process at the mill. Exemplary masonry mortar
compositions of the invention accordingly comprise a hydratable
cementitious binder, an entrained air content of 14% or less, and
the multi-stage polymer having a hydrophobically-modified,
ionically-soluble polymer stage and an air-entraining agent, as
above-mentioned and as will be further described hereinafter.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
The masonry mortar additives of the present invention comprise
water; a multi-stage polymer comprising a hydrophobically-modified,
ionically-soluble polymer stage, the polymer being soluble at a pH
of 6 and above; and an entraining agent.
An exemplary multi-stage polymer suitable for use in the present
invention comprises two or more polymer stages wherein:
(A) at least one of said polymer stages is an ionically-soluble
polymer, the ionically-soluble polymer being polymerized from a
monomer mixture comprising:
(a) about 0.1 to about 55% by weight hydrophobic monomer having the
formula ##STR1##
R.sub.1 and R.sub.5 independently are (C.sub.1 -C.sub.30) alkyl, a
(mono, di-, or tri-) (C.sub.1 -C.sub.30) alkyl-substituted phenyl
ring, or a sorbitan fatty ester; R.sub.2, R.sub.3 and R.sub.4
independently are --H or (C.sub.1 -C.sub.10) aklyl, aryl or
alkylaryl; a is 0 or 1; b is 0 to 50; c is 0 to 150; d is 0 to 50;
e is equal to or greater than 1 and X is a group containing at
least one ethylenic double bond;
(b) about 10 to about 69% by weight (C.sub.3 -C.sub.30)
ehtylenically-unsaturated, ionizable monomer, and
(c) about 0.1 to about 90% by weight nonionic (C.sub.2 -C.sub.30)
ethylenically-unsaturated monomer, and
(d) 0 to about 10% by weight multi-functional compounds;
(B) the ionically-soluble polymer is physically or chemically
attached to the polymer particle such that, upon neutralizing the
ionically-soluble polymer with base or acid, at least a portion of
said ionically-soluble polymer remains attached to the remainder of
the polymer particle; and
(C) the ionically-soluble polymer comprises from about 1% to about
99% by weight of the polymer particle. A multi-stage polymer, which
comprises at least one hydrophobically-modified, ionically-soluble
polymer stage is disclosed in U.S. Pat. No. 5,451,641 assigned to
Rohm and Haas Company, Philadelphia, Pa. A suitable polymer is
commercially available from Rohm and Haas under the tradename
ACRYSOL.RTM. TT-165. The multi-stage polymer is an alkali-soluble
acrylic polymer emulsion, which is typically used for textile
formulations, such as for paper, textiles, and nonwovens, although
it is also sold for pigmented caulks.
Exemplary air-entraining agents (AEAs) suitable for use in the
present invention comprise nonionic AEAs such as fatty
alkanolarnides, ethoxylated fatty amines, ethoxylated fatty acids,
ethoxylated triglycerides, ethoxylated alkylphenols, ethoxylated
alcohols, alkyl ethoxylates, alkylaryl ethoxylates; cationic AEAs
such as amine ethoxylates and amine oxides; amphoteric AEAs such as
betaines; and anionic AEAs such as fatty alkyl ether sulfates,
fatty alkylaryl ether sulfates, alkyl benzene sulfonates,
sulfosuccinates, and fatty sulfonates. AEAs useful in the present
invention must be soluble at a pH range of 3-6 to obtain solubility
in the cementitious mixture, and must also be soluble at a pH of
10-11 and above in view of the hydration process taking place in
the mortar. Thus, the AEA must have a fairly wide solubility
range.
A preferred air-entraining agent is available from Rhone Poulenc
under the tradename Cyclomide DC 212/S.
An exemplary method of the present invention comprises adding to a
mortar cement, preferably during the intergrinding of the cement at
the mill, the multi-stage polymer in an amount of 0.005-0.10% by
weight based on the weight of the cement, and more preferably about
0.015-0.10% by weight cement, and the air entraining agent
preferably in an amount of 0.001-0.02% based on the weight of the
cement. Preferably, the addition is achieved using a one-time
introduction of the multi-stage polymer and air entraining agent
which are pre-mixed together as an emulsion. The emulsion can
comprise 20-80% water.
Further exemplary mortar additives of the invention optionally
comprise, in addition to the multi-stage polymer and air entraining
agent, a set retarder (0-35% by total weight) and a
superplasticizer. Water-soluble set retarding agents for Portland
cement are well known and are preferred for use in the present
invention. If the additive is provided in the form of an emulsion,
then the set-retarding component of the additive should not be such
that it destabilizes the emulsion or causes the additive to be
overly viscuous.
Water-soluble set-retarding agents useful in the present invention
include carbohydrates such as monosaccharides, for example, glucose
and fructose; disaccharides, for example, raffinose;
polysaccharides, for example, starch and cellulose as well as
derivaties thereof, such as pregelatinized starch, dextrin, corn
syrup and carboxymethylcellulose; polyhydroxy polycarboxylic
compounds, such as tartaric acid and mucic acid; lignosulfonic acid
and salts thereof such as calcium, magnesium, ammonium and sodium
lignosulfonate; water-soluble salts of boric acid, such as the
alkali metal salts thereof; zinc oxide, and water-soluble silicone
compounds; as well as mixtures thereof. A preferred retarder is
sucrose. The retarders can be used in an amount of about 10-40% wt.
in the solution.
An exemplary superplasticizer which may optionally be used in the
masonry additives and methods of the invention are EO/PO type comb
polymers (e.g., a polyacrylic acid having pendant polyethylene
oxide and polypropylene oxide pendant groups) which are known. A
suitable EO/PO type superplasticizer is available from W. R. Grace
& Co.-Conn. under the tradename ADVA. It is believed that the
superplasticizer may be employed in the masonry mortar additives of
the present invention in an amount of 0-30% wt. in the
solution.
Preferably, the foregoing identified multi-stage polymer and air
entraining agent, along with the optional set retarder and/or
superplasticizer, are pre-mixed together in a single emulsion so as
to minimize overdosing, and introduced into the mortar cement,
preferably during or before the intergrinding of the Portland
cement in the mill. Alternatively, the components and optional
components may be introduced into a mortar cement after the
grinding process.
The foregoing description and examples are set forth for
illustrative purposes only, and not intended to limit the scope of
the invention.
* * * * *